This particular lens has a maximum focal length of 21 mm and a minimum focusing distance of 0.32 m. The aperture on the lens ranges from ƒ/32 to ƒ/4.
From WEX Photo Video
Hasselblad 21mm f4 XCD Lens
Clifton Cameras
Hasselblad 21mm f4 XCD Lens
Scan
Hasselblad XCD 4/21 Lens